First Case of New World Screwworm Detected in Coahuila, Mexico

The Texas Department of Agriculture confirmed a New World Screwworm case about 119 miles from the Texas border, near Zapata, Texas, and north and west of the Rio Grande Valley.

Aberdeen Angus Cattle Feeding in a Feedlot at Sunset

Angus cattle feeding in a feedlot at sunset

JavierAndrés - stock.adobe.com

AUSTIN, TEXAS (RFD NEWS) — Texas Agriculture Commissioner Sid Miller is warning producers to stay alert after the first confirmed detection of New World screwworm in the Mexican state of Coahuila, bringing the pest closer to the U.S. border.

According to the Texas Department of Agriculture, the detection was confirmed roughly 119 miles from the Texas border, placing it near the same latitude as Zapata, Texas, and north and west of the Rio Grande Valley.

“This screwworm detection in Coahuila is a serious wake-up call,” Miller said. “New World screwworm has now been found only 119 miles from the Texas border — at roughly the same latitude as Zapata, Texas, and north and west of the Rio Grande Valley.”

New World screwworm is a parasitic fly whose larvae infest living tissue in warm-blooded animals, causing severe wounds known as myiasis. Officials say adult flies lay eggs in open wounds or mucous membranes, and once the larvae hatch, they burrow deeper into tissue, rapidly worsening injuries and potentially killing livestock if left untreated.

The pest poses a threat to cattle, horses, sheep, goats, wildlife, pets, and in rare cases, humans.

“This threat is advancing fast, and every Texan needs to take notice,” Miller said.

Texas officials say the state has expanded its biosecurity response in recent months, including additional trapping efforts in high-risk border areas, export facilities, and port zones.

“Texas is on the front lines,” Miller said. “Under my direction, the Texas Department of Agriculture has launched an aggressive biosecurity response, including expanded trapping with our innovative TDA Swormlure in high-risk border zones, export pens, and port areas. We are conducting weekly surveillance, maintaining rapid response capabilities, and working in close coordination with federal partners and Mexico.”

Miller said Texas is relying on lessons learned from past eradication efforts, including the sterile insect technique that helped eliminate screwworm from the U.S. decades ago.

“We’ve beaten the screwworm before through relentless vigilance and the sterile insect technique. We will beat it again — but we must deploy every tool available,” Miller said. “Texas will stay vigilant, stay aggressive, and do whatever it takes to protect our livestock, our pets, our food supply, and the livelihoods of our ranchers.”

Texas producers who suspect an infestation are encouraged to contact their veterinarian immediately or call the Texas Department of Agriculture hotline.

More information is available from the U.S. Department of Agriculture at www.Screwworm.gov.

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